You're browsing the WordPress hooks database, which contains information about action hooks and filter hooks in WordPress's code. The hooks in WordPress make it the most flexible blogging software available. Plugin authors and theme developers rely on WordPress hooks to interact with the blog platform's PHP code. More information about this database is at WordPress Hooks Database (home). You may also be interested in my easy PHP tutorial for WordPress users. Note that my website is not a WordPress support forum, though; you should ask you WP questions over at the WordPress support forums.